The detection of the meq gene in chicken infected with Marek's disease virus serotype 1   总被引：4，自引：0，他引：4  

Chang KS  Lee SI  Ohashi K  Ibrahim A  Onuma M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(5):413-417

In the genome of strains of very virulent Marek's disease virus serotype 1(vvMDV1), such as Md5 and RB1B, the meq open reading frame (ORF) encoding a 339-amino-acid bZIP protein, is present, while a slightly longer meq ORF, termed as L-meq, in which a 180-bp sequence is inserted into the meq ORF is found in other strains of MDV1, such as CV1988/R6 and attenuated JM. When chickens were infected with vvMDV1 strains and the meq gene was amplified by nested polymerase chain reaction (PCR), the meq gene was detected throughout the experimental period for 7 weeks post inoculation (pi). However, the L-meq gene was also detected at 3 to 5 weeks and 3 to 4 weeks pi. in Md5-infected and RB1B-infected chickens, respectively. In the case of chickens infected with an attenuated MDV1, the JM strain, the L-meq gene was detected at 2 to 7 weeks pi., and the meq gene was also detected at 2 to 6 weeks pi. Both L-meq and meq genes were detected in chickens infected with an attenuated nononcogenic vaccine strain of MDV1 (CVI988/R6), throughout the experimental period. Though quantitative PCR was not performed, a larger amount of the PCR products corresponding to the L-meq than the meq gene was amplified from chickens infected with JM or CVI988/R6. These results suggest that a dynamic population shift between the MDV subpopulations displaying meq and L-meq genes occurs in chickens during the course of MDV infection. Since the MDV subpopulation that displays the L-meq gene only displays it during the latent phase, the L-meq and its gene product, if any, might contribute to the maintenance of the MDV latency.  相似文献   

Ameliorative effects of sodium bentonite on phagocytosis and Newcastle disease antibody formation in broiler chickens during aflatoxicosis   总被引：1，自引：0，他引：1  

Ibrahim IK  Shareef AM  Al-Joubory KM 《Research in veterinary science》2000,69(2):119-122

The ameliorative effect of graded levels of dietary sodium bentonite (0.2, 0.4 and 0.6 per cent wt/wt of feed) on in vitro-impaired phagocytosis and suppressed immune response to Newcastle disease vaccine during aflatoxicosis (AF) in broiler chicks was investigated. Both percentage and mean of phagocytic activities were decreased significantly (P < 0.05) in chicks fed 2.5 mg aflatoxin per kg feed. The addition of sodium bentonite was significantly effective in ameliorating the negative effect of AF on the percentage and mean of phagocytosis. The presence of AF alone in the diet depressed the immune response of chicks as measured by haemagglutination inhibition (HI) test. Sodium bentonite was also effective in ameliorating the suppressive effect of AF on the HI -titre in chicks vaccinated against Newcastle disease. The best results obtained when sodium bentonite was added at the rate of 0.4 per cent wt/wt of feed to the AF-containing diets.  相似文献   

Effect of temperature and photoperiod on development and fecundity of an acarophagous ladybird beetle,Stethorus gilvifrons     

Tulin Aksit  Ibrahim Cakmak  Gamze Ozer 《Phytoparasitica》2007,35(4):357-366

The development, fecundity and survival ofStethorus gilvifrons Mulsant (Coleoptera: Coccinellidae) fed onTetranychus cinnabarinus Boisduval (Acari: Tetranychidae) were recorded at three constant temperatures (20, 25 and 30±1°C) and 50±10% relative humidity, under two photoperiods (16:8 L:D and 8:16 L:D) produced using artificial light (4000 lux). The development rate for the egg stage (r_[Te]) increased linearly with increasing temperature (r_[Te]=0.0132*T ? 0.0955; R²=0.95). The theoretical egg-development threshold was estimated to be 7.24°C; 75.75 degree-days (DD) were required for hatching. The total development time (r_[Tt]) also decreased linearly with increasing temperature (r_[Tt]=0.0039*T ? 0.0325; R²=0.98). The development threshold was estimated to be 8.33°C and full development from egg to adult required 256.41 DD. Higher temperatures resulted in a shorter generation time (T ₀) and decreased net reproductive rate (R ₀). The length of the previposition and postoviposition period, as well as longevity, decreased significantly with increasing temperature under both photoperiods. The oviposition and postoviposition periods, longevity, and total fecundity were not significantly affected by photoperiod. The values of both the intrinsic rate of increase (r _m ) andR ₀ were highest under the long-day photoperiod at 25°C. The mortality rate was lowest at 20°C under the short-day photoperiod. Of the conditions tested, the optimum temperature for rearingS. gilvifrons was 25°C and the optimum photoperiod was 16:8 L:D.  相似文献   

Effect of cultural practices on the development of arabica coffee berry disease,caused by <Emphasis Type="Italic">Colletotrichum kahawae</Emphasis>     

Joseph Aubert Mouen Bedimo  Daniel Bieysse  Ibrahim Njiayouom  Jean Pierre Deumeni  Christian Cilas  Jean Loup Nottéghem 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(4):391-400

In the high altitude regions of Africa, coffee berry disease (CBD), caused by Colletotrichum kahawae, is the main constraint for arabica coffee (Coffea arabica) production. However, certain agricultural practices can reduce losses caused by the disease and thereby promote optimum production. On small family farms in Cameroon, mixed cropping with fruit trees, intercropping with food crops and maintenance pruning of coffee trees are very widespread agricultural practices that can affect CBD epidemics. Consequently, an epidemiological study was conducted to assess how cultural practices affected the disease in an arabica coffee smallholding in Cameroon. The disease was monitored on a weekly basis over four successive years (2002–2005) on coffee trees in diverse cultural situations. Cultural practices likely to reduce losses due to CBD were identified. The infection rate was significantly lower on coffee trees grown intensively than on coffee trees grown in the traditional manner. Coffee trees located under the shade of fruit trees were significantly less attacked than those located in full sunlight. In addition, berries on the leafless parts of branches, near the main trunk of the coffee tree, were less infected than those on leafy sections. These results show that maintenance pruning, removal of mummified berries, and mixed cropping with shade plants are cultural practices which create environmental conditions that limit CBD development.  相似文献   

A study on bluetongue virus infection in Saudi Arabia using sentinel ruminants     

Abu Elzein EM  Aitchison H  al-Afaleq AI  al-Bashir AM  Ibrahim AO  Housawi FM 《The Onderstepoort journal of veterinary research》1998,65(4):243-251

Four sentinel herds comprising cattle, sheep and goats were established at various localities in Saudi Arabia. Maternal bluetongue antibodies were detected in all four sentinel herds but disappeared in 4-6 months, immediately followed by seroconversion in all. Serological results indicated that the animals were recently exposed to BT virus serotypes 10, 12, 15 and 20. The epidemiology of the disease in Saudi Arabia is discussed.  相似文献   

Optimizing supplemental irrigation: Tradeoffs between profitability and sustainability     

Theib Oweis  Ahmed Hachum 《Agricultural Water Management》2009,96(3):511-516

Water production functions are used to model yield response to various levels of supplemental irrigation (SI), to assess water productivity coefficients, and to identify optimum irrigation under various input-output price scenarios. The SI production function is taken as the difference between the total water production function (irrigation + rain) and that of rainwater. Theoretical analysis of the unconstrained objective function shows that the seasonal depth of SI to maximize profit occurs when the marginal product of water equals the ratio of unit water cost to unit product sale price. Applying this analysis to wheat in northern Syria, the production functions of SI under different rainfall conditions are developed. Coupled with current and projected water costs and wheat sale prices, the functions are used to develop an easy-to-use chart for determining seasonal irrigation rates to maximize profit under a range of seasonal rainfall amounts.Results show that, for a given seasonal rainfall, there is a critical value for the ratio of irrigation cost to production price beyond which SI becomes less profitable than rainfed production. Higher product prices and lower irrigation costs encourage the use of more water. Policies supporting high wheat prices and low irrigation costs encourage maximizing yields but with low water productivity. The resulting farmer practice threatens the sustainability of water resources. Balancing profitability versus sustainability is a challenge for policy makers. Our analysis can help national and local water authorities and policy makers determine appropriate policies for water valuation and allocation; and assist extension services and farmers in planning irrigation infrastructure and farm water management.  相似文献   

银合欢落叶层对苗圃生长的森林一农田作物的他感作用(英文)     

Romel Ahmed  A. T. M. Rafiqul Hoque  Mohammed Kamal Hossain 《林业研究》2008,19(4)

利用随机区组试验评估了孟加拉国吉大港大学苗圃内的银合欢落叶对森林作物种白格、黄金檀和农田作物种长豇豆、鹰嘴豆和木豆的他感作用。结果表明,凋落叶诱导抑制作物的萌发和生长,该抑制作用依赖于萃取物浓度、凋落物及受体物种类型。萃取物浓度越高则他感作用越强。受体植物的生长响应随应用的凋落叶而变化。低浓度(10g·m-2)凋落叶对农田作物嫩芽生长有促进作用,而其他浓度的凋落叶则呈现明显的抑制作用,施用的凋落叶浓度越大抑制作用也越大。但是不同处理所表现出的抑制趋势并不均一,根系生长受到的影响大于嫩芽。图3表4参34。  相似文献   

黄瓜游离小孢子培养诱导成胚和植株再生   总被引：4，自引：0，他引：4  

詹艳  陈劲枫 《园艺学报》2009,36(2):221-226

 以10个不同基因型黄瓜为试材进行游离小孢子培养，通过对成胚条件的系统研究，从‘7447’和‘Poinsett97’中获得了子叶形胚和再生植株。研究结果表明：基因型和小孢子发育时期是限制黄瓜游离小孢子成胚的关键因子。不同品种间胚状体产量差异显著，每皿产胚1.5～33.4个。单核靠边期是进行黄瓜游离小孢子培养的最佳时期。低温预处理有利于胚状体的诱导，4 ℃预处理2～4 d为宜，以处理2 d时胚状体产量最高。外源激素在诱导胚状体时并非必需，但低浓度的外源激素（0.5 mg·L^-1 2,4－D、0.2 mg·L^-1 6－BA）更能促进小孢子成胚。NLN和B5两种基础培养基在诱导胚状体上无显著差异。子叶形胚易分化成苗，而其它类型的胚状体不能获得再生植株。  相似文献   

Effects of Stocking Density and Monosex Culture of Freshwater Prawn Macrobrachium rosenbergii on Growth and Production in Concrete Tanks in Saudi Arabia     

Abdul Qayyum  Siddiqui  Yousef S.  Al-Hafedh  Ahmed H.  Al-Harbi Seikh A.  Ali 《Journal of the World Aquaculture Society》1997,28(1):106-112

Abstract This study was conducted to evaluate the effects of stocking density and monosex culture on growth, survival, yield and feed conversion ratio of freshwater prawn Macrobrachium rosenbergii in concrete tanks. Juvenile prawns with an average weight of 1.8 g were stocked into triplicate tanks at densities of 5, 10, 15 and 20 prawns/m², grown for 168 d and fed a 34% tilapia diet. Stocking density had significant effect on prawns. Final mean body weight decreased with the increasing density, being highest at 5 prawns/m² (29.6 9). and lowest at 20 prawns/m² (17.4 g). Total yield increased from 135 g/m² (1,350 kg/ha) at a density of 5 prawns/m² to 261 g/m² (2,610 kg/ha) at density 15/m^z to 245 g/m² (2,450 kg/ha) at 20/m^z. Feed conversion ratios were high and ranged from 3.7 (5 prawns/m²) to 5.6 (20 prawns/m²).
In monosex culture of freshwater prawns stocked in triplicate tanks at a density of 5 prawns/m² for 112 d, the all-male population had the best growth performance and feed conversion ratio, followed by the mixed-sex and all-female populations. The all-male population had 99% marketable prawns (>20 g) with an average yield of 159 g/m² (1,590 kg/ha); the mixed-sex population had 90% marketable prawns and the yield was 135 g/m^z (1,350 kg/ha); and the all-female population had 75% marketable prawns with an average yield of 108 g/m² (1,080 kgha).  相似文献   

MicroRNA-21 expression,serum tumor markers,and immunohistochemistry in canine mammary tumors     

Ramadan  Eman S.  Salem  Noha Y.  Emam  Ibrahim A.  AbdElKader  Naglaa A.  Farghali  Haithem A.  Khattab  Marwa S. 《Veterinary research communications》2022,46(2):377-388

Background

Canine mammary tumors (CMTs) are one of the most common malignancies in dogs and are associated with significant mortality. Serum tumor markers and non-coding microRNAs have gained widespread popularity in human oncology studies. The present study has two aims, first one is to investigate the miR-21 expression compared with changes in serum tumor markers (CEA and CA15-3) in CMT. The second aim is to detect the immunohistochemistry markers as vimentin, P63, and -SMA in CMT.

Methods

This study enrolled 17 female dogs: 10 with mammary tumors and seven controls without tumors. Blood samples were collected to measure miR-21, CEA, and CA 15-3, and histological samples were prepared for histological grading and immunohistochemistry.

Results

CA 15-3 was elevated in all animals, whereas CEA levels showed no change compared with controls. miR-21 was upregulated 12.84-fold in animals with CMT. The most frequently recorded CMT was the mixed type. Myoepithelial cells were identified by P63 immunoreactivity, but not SMA. High expression of miR-21 was observed with positive vimentin immunoreactivity, indicating the mesenchymal origin of the tumor cells.

Conclusion

The present study showed that miR-21 was elevated to a greater extent than CA 15-3 (12.84-fold vs. threefold). Tumors that was positive for vimentin immunoreactivity was also associated with an elevation in the levels of miR-21, showing that miR-21 is released from mesenchymal cells. These findings support the hypothesis that miR-21 may be a more sensitive, noninvasive indicator for CMT.

  相似文献